Monomer recovery process

Abstract

To provide a process for recovering and recycling a monomer and a solvent in a waste supply stream resulting from a copolymer polyol manufacturing process.SOLUTION: A process including the steps of:(a) providing a waste supply stream containing a styrene monomer, an acrylonitrile monomer, a solvent and impurities and resulting from a copolymer polyol manufacturing process; (b) subjecting the waste supply stream of step (a) to a separation process under conditions for separating the monomers and solvent from the impurities, the separation process including forming a plurality of overhead streams, a side stream, and a bottom stream; (c) recovering the monomers and solvent in the plurality of streams; and (d) passing the one or more of the monomer and solvent from step (c) to a supply stream of a copolymer polyol manufacturing process.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a process for recovering monomers and solvents from waste streams generated by a copolymer polyol (CPP) composition production process.

Summary of the Invention

Problems to be Solved by the Invention

[0002] Generally, in a production process for producing polyurethane foam, a reaction mixture of a polyol with other additives such as a polyisocyanate and a catalyst is used to prepare a foam-forming polyurethane reaction mixture composition, and this can be used to produce a polyurethane foam. Copolymer polyol (CPP) can be used as a polyol reactant in the reaction step of the foam manufacturing process and is highly desired. That is, the CPP reactant reacts with the polyisocyanate reactant in the production of polyurethane (PU) foam. A typical CPP product can be a stable dispersion of styrene-acrylonitrile (SAN) copolymer particles suspended in a polyether polyol.

[0003] Heretofore, known CPP stable dispersion products used as reactants in the foam-forming process usually have a significant concentration of residual monomers (especially, for example, styrene and acrylonitrile monomers) present in the final CPP dispersion product after CPP is produced. The residual monomers are the unreacted portions of the reactants from the dispersion polymerization reaction step before the process for producing SAN particles in the polyether polyol is carried out. To produce SAN particles In this process, typically, residual monomers are produced after the polymerization reaction step described above. Then it is stripped. Typically, stripping is done in various different ways (for example, back Various stripping agents (e.g., in a single-stage or multi-stage system) in a continuous system, single-stage or multi-stage This can be done using nitrogen, isopropanol, steam, etc.

[0004] Referring to Figure 1, we see the first reactor 20, the second reactor 30, and the distillation column 40 (for example, S A tripping tower (40) and a waste storage container (50) are included for producing CPP products. The known general process, generally indicated by reference number 10, is shown. In this process, the monomer supply stream 21 enters the first reactor 20, and the supply stream The monomers such as styrene and acrylonitrile present in Room 21 are partially reacted. Next, the reaction mixture is transferred to the second reactor 30 via stream 22. In reactor 30, the monomers further react to form the CPP product, residual monomers, and soluble A mixture with the medium is formed, which exits the reactor 30 as stream 31. Then, Ream 31 is moved to the distillation / stripping column 40 to remove waste products from the CPP product. Separate (i.e., strip) any undesirable material. CPP product The waste products exit the tower 40 as a product stream 41 and are transferred to a waste storage container 50. The moving waste product stream 42 exits tower 40. In relation to the known CPP process described above. One major challenge is the distribution of styrene and acrylonitrile in waste stream 42. A considerable amount of beneficial residual monomers still remains. Another problem is, This is a significant loss of unreacted monomers and solvent, which is wasteful. Typically, this Until then, the waste stream 42 is disposed of or stored in storage unit 5 awaiting disposal. It was sent to 0. The recovered residual monomers are being reused in monomer supply stream 2. From the stripped waste stream 42, it can be recycled back to 1. To provide a novel process that removes all or substantially all of the residual monomers. It would be desirable and advantageous. Such desirable new CPP processes have been known for some time. This could be more efficient and lower cost than the CPP production process for knowledge.

[0005] Various prior art references describe the partial recovery of monomers and solvents as a mixture. Various methods are mentioned. However, using such mixtures as a recirculation stream To use it, additional steps are necessary. For example, using a prior art process. Therefore, the removal of unwanted impurities that may be present in the stripped waste stream is It hasn't been addressed at all. Such impurities exist in the stream that is being recycled. In some cases, impurities present in the recirculated stream can seriously affect the quality of the CPP product produced. This has an impact, and consequently, a serious impact on the quality of forms produced using such CPP. It could have a significant impact.

[0006] Another problem plaguing prior art processes is the rotation of acrylonitrile residual monomers. The difficulty lies in the fact that acrylonitrile forms a minimum boiling azeotropic mixture with water. There is a tendency for such azeotropic mixtures to form during the CPP production process. This is because it is very difficult to separate acrylonitrile monomers. Prior art None of the references solve the problem of separating water from the minimum boiling azeotrope of acrylonitrile and water. For example, CN104045773A discloses the use of styrene and acrylonitrile monomers, as well as the use of isopropyl alcohol (IPA) solvent in the separation and recovery method for solvents during the production process of polymer polyols. The above reference describes the recycling of solvents with a specific composition, but the above reference does not mention how the solvent is separated from the product, nor does it mention the recovery or recycling of monomers.

[0007] CN106866893A discloses a method for preparing high solids low volatile organic compound (VOC) polymer polyols, and also describes the use of a recycling container for monomer waste streams. However, the monomer waste stream is not purified before the waste stream is used.

[0008] U.S. Patent No. 2,807,573A discloses the purification of acrylonitrile by extractive distillation, and also describes the purification of a mixture of acrylonitrile and acetonitrile using a solvent. The solvents mentioned in the above patent include aqueous alkali salts. However, the above patent teaches the separation of the acrylonitrile - water azeotrope from a mixture containing acrylonitrile, acetonitrile, and water, but does not teach the decomposition of the azeotrope into the individual components in the azeotrope.

[0009] U.S. Patent No. 3,445,347 discloses extractive distillation of acrylonitrile with the removal of a side stream of an impurity stream and also describes the use of water as an extraction solvent. The acrylonitrile-water azeotrope is collected at the top of the column, but the components of the azeotrope are not separated from each other. The matter in International Journal of Chemical and Molecular Engineering, Vol. 9, No. 2, 2015 describes the use of different entrainer solvents for the extractive distillation of acetonitrile (not acrylonitrile). The solvents described in the above reference include butyl acetate, DMSO, ethylene glycol, DMF, glycerol, and pyridine, with glycerol being preferred. The article in Chemical Engineering Research and Design, 99(2015), pp 125 - 131 discloses the separation of ternary mixtures by extractive distillation using 1,2 - ethanediol and glycerol and also describes the use of DMSO and glycerol for the extractive distillation of acrylonitrile - water. The aforementioned references and other prior art references do not provide a method for separating water from the minimum boiling azeotrope of acrylonitrile and water. It is desirable to provide a solution to the above problem. The present invention provides a step of (a) providing a waste feed stream containing monomers, solvents, and impurities, and (b) separating the waste feed stream of step (a) into a waste stream

[0010] International Journal of Chemical and Molecular Engineering,Vol.9,No.2,2015 describes the use of different entrainer solvents for the extractive distillation of acetonitrile (not acrylonitrile). The solvents described in the above reference include butyl acetate, DMSO, ethylene glycol, DMF, glycerol, and pyridine, with glycerol being preferred. The matter in International Journal of Chemical and Molecular Engineering, Vol. 9, No. 2, 2015 describes the use of different entrainer solvents for the extractive distillation of acetonitrile (not acrylonitrile). The solvents described in the above reference include butyl acetate, DMSO, ethylene glycol, DMF, glycerol, and pyridine, with glycerol being preferred. The matter in International Journal of Chemical and Molecular Engineering, Vol. 9, No. 2, 2015 describes the use of different entrainer solvents for the extractive distillation of acetonitrile (not acrylonitrile). The solvents described in the above reference include butyl acetate, DMSO, ethylene glycol, DMF, glycerol, and pyridine, with glycerol being preferred. The solvents described in the above reference include butyl acetate, DMSO, ethylene glycol, DMF, glycerol, and pyridine, with glycerol being preferred. The solvents described in the above reference include butyl acetate, DMSO, ethylene glycol, DMF, glycerol, and pyridine, with glycerol being preferred.

[0011] Chemical Engineering Research and Desi gn,99(2015),pp 125-131 describes the separation of ternary mixtures by extractive distillation using 1,2 - ethanediol and glycerol and also describes the use of DMSO and glycerol for the extractive distillation of acrylonitrile - water. Chemical Engineering Research and Desi gn,99(2015),pp 125-131 describes the separation of ternary mixtures by extractive distillation using 1,2 - ethanediol and glycerol and also describes the use of DMSO and glycerol for the extractive distillation of acrylonitrile - water. The aforementioned references and other prior art references do not provide a method for separating water from the minimum boiling azeotrope of acrylonitrile and water. The aforementioned references and other prior art references do not provide a method for separating water from the minimum boiling azeotrope of acrylonitrile and water. It is desirable to provide a solution to the above problem.

[0012] The present invention provides a step of (a) providing a waste feed stream containing monomers, solvents, and impurities, and (b) separating the waste feed stream of step (a) into a waste stream 提供するステップと、(b)ステップ(a)の廃棄物供給ストリームを、廃棄物ストリー A state subjected to a separation process under conditions for separating monomers and solvents from impurities in a substance. (c) a step of recovering monomers and solvents in one or more streams, ( d) One or more streams of monomer and solvent from step (c) to further The process includes the step of moving the waste stream to a processing facility, and the process of removing monomers and solvents present in the waste stream. This focuses on the process for recovering the medium.

[0013] In one preferred embodiment, monomers present in the waste stream are recovered. The process involves (a) at least one solvent and at least one styrene monomer - and a waste supply stream containing at least one acrylonitrile monomer (b) the waste supply stream from step (a), or pre-distilled A step of subjecting the mixture to extractive distillation, wherein the mixture is a solvent, styrene monomer and The sterol can contain at least one monomer and water as an azeotropic composition. (c) From the waste supply stream of step (a), solvent, styrene monomer, (d) a step of separating the acrylonitrile monomer, and (d) recirculation, further processing, Alternatively, for storage, the solvent, styrene monomer, and a solvent in two or more separate streams. The process includes the step of recovering the crironitrile monomer.

[0014] In another embodiment, the solvent, styrene, is separated and recovered by the process of the present invention. The monomers and streams of acrylonitrile monomers produce copolymer polyols. The separation and recovery method of the present invention can be used in the process for production, and (1) Mo (1) one of the nomers (e.g., styrene or acrylonitrile), (2) a solvent, teeth (3) Solvent from waste stream (e.g., toluene or isopropanol) In addition, any favorable combination of monomers (e.g., styrene and acrylonitrile) To produce a stream with a purity of over 98.5 percent (>) of either of the following: It can be used for that purpose.

[0015] Typically, it contains a solvent, a styrene monomer, and an acrylonitrile monomer. The waste streams are collected separately during known processes for producing CPP products. On the other hand, in the present invention, the pure streams of monomer and solvent are used to generate waste. It can be recovered from the stream, and then the pure stream is used in the CPP production process. The material is recycled and returned to the reactor in which it is used. The process of the present invention is used in the CPP production process. It provides a significant reduction in the amount of waste produced, and also reduces the amount of raw materials consumed in the CPP production process. It provides a significant reduction.

[0016] Styrene and toluene are distilled using conventional distillation equipment (e.g., batch distillation or continuous distillation). ) can be easily recovered from process waste streams. However, The water present in the waste stream (typically less than 1 weight percent [weight]) , to form a minimum boiling azeotropic mixture with acrylonitrile, conventional distillation is used. Dehydrating acrylonitrile is not practical. In one embodiment of the present invention, acrylonitrile and water The problem of separating water from a minimum boiling azeotropic mixture can be solved. For example, preferred In the embodiment, an entrainer is used to control the relative volatility of the acrylonitrile-water system. The mixture can be altered and the azeotropic mixture can be decomposed. In another preferred embodiment, triply Glycols such as lenglycol (TPG) are used in the entrainer of the extraction distillation sequence. Use it to separate water from a stream of >98.5% pure acrylonitrile. This can be done. Water is not the desired product in the CPP production process, and therefore water is The water is not recycled back into the reactors of the CPP production process. Instead, the water is recycled. Since water accumulates in the system, it is desirable that water be removed from the process of the present invention.

[0017] Pervaporation or adsorption separates water from the acrylonitrile stream. It is an alternative method that can be used for that purpose. However, the high reactivity of acrylonitrile is a disadvantage. The following limits the suitable membrane or adsorbent materials that can be used as alternatives to the above methods. Due to the high reactivity and toxicity of acrylonitrile, pervaporation is very Because they are expensive and difficult to handle, the films used in the pervaporation method have high turnover rates. It has an over-consumption rate. Glycols such as TPG are relatively inexpensive solvents, and acrylon It possesses desirable and necessary properties for removing water from a toril-water azeotrope stream. Extractive distillation Using glycols such as TPG in sequencing offers advantages. It can produce a stream of 98.5% pure acrylonitrile. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 is a schematic flow chart of the prior art process for producing CPP products. [Figure 2] Figure 2 is a schematic flow chart of the process of the present invention for producing CPP products. [Figure 3] Figure 3 is a schematic flow diagram of the process of the present invention for separating and recovering residual monomers and solvents from a waste stream. [Figure 4] Figure 4 is a schematic flow diagram of one embodiment of the process of the present invention for separating and recovering residual monomers and solvents from a waste stream. [Figure 5] Figure 5 is a schematic flow diagram of yet another embodiment of the process of the present invention for separating and recovering residual monomers and solvents from a waste stream. [Figure 6] Figure 6 is a schematic flow diagram of yet another embodiment of the process of the present invention for separating and recovering residual monomers and solvents from a waste stream. [Figure 7] Figure 7 is a schematic flow chart of the extraction distillation process of the present invention for separating and recovering residual monomers and solvents from a waste stream. [Figure 8] Figure 8 is a schematic flow diagram illustrating the overall process of the present invention for separating and recovering various residual monomers and solvents from a waste supply stream. [Modes for carrying out the invention]

[0019] The copolymer polyol (CPP) reaction product is suspended in the polyether polyol. This is a stable dispersion of styrene-acrylonitrile (SAN) copolymer particles. During the production process for producing PP reactant products, the SAN-CPP stripping step is performed. A waste stream is produced from this. The waste stream is, for example, acrylonitrile. It may contain styrene, toluene, ethylbenzene, water, and other heavy impurities. In one broad embodiment, the present invention relates to the aforementioned materials such as acrylonitrile and styrene. The monomers are separated from the waste stream and the monomers are recycled into CPP production plants. This process includes recycling the process back into the pipeline.

[0020] Referring to Figure 2, the waste stream containing residual monomers and solvents (CPP Instead of discarding the waste generated in the process of producing the finished product, the process is significantly different from that of prior art. The present invention, generally referred to as reference number 100, is for producing different CPP products. The process is shown, and the waste stream is further processed and monomers are recycled in the CPP process. Residual monomers and solvents are separated and recovered for reuse (recycling). The process is advantageously efficient and uses residual monomers in the CPP production process. And it saves on solvent-related costs.

[0021] Referring again to Figure 2, the CPP production process 100 is generally referred to by reference number 200. A monomer separation and recovery system for separating and recovering one or more monomers, as shown. It is shown to include a stem or scheme, and monomer streams coming out of recovery process 200 The compost and solvent 211 are recirculated back to the supply stream 121 of the CPP process. This is possible. For example, stream 211 can be combined with supply stream 121 to perform the first A supply stream 212 can be formed that moves to reactor 120. First reactor The output stream 122 from reactor 120 goes to the second reactor 130. From 30, output stream 131 moves to distillation column 140. In distillation column 140, CP The P-product stream 141 is separated from the waste stream 142, and this is the waste stream The residual monomers in the supply stream 142 are recycled to the CPP supply stream 121. A recovery process 200 for separating into one or more monomer streams 211 Move. The monomer separation and recovery system 200 shown in Figure 2 is a versatile system. Examples of some preferred embodiments of such systems are provided herein. This will be explained in more detail below.

[0022] Referring to Figure 3, monomers such as acrylonitrile and styrene are used in waste slits. One of the processes of the present invention, generally referred to as reference number 300, for separating from the frame A schematic flowchart of a wide range of embodiments is shown. The process of the present invention 300 is, for example, However, this involves several distillation operations not found in prior art processes, such as novel extractive distillation operations. It can include. Generally, process 300 consists of one or more towers, process steps, and This may include an operational scheme, generally indicated by reference number 310. For example, supply and disposal. The material stream 311 can move to one or more distillation columns 310, and one or more material The Mer product stream and solvent stream 312 exit column 310. In addition, heavy Object stream 313, overhead stream 314, and side stream 315 One or more waste streams, such as those described herein, can exit Tower 310. "Heavy materials" refer to the process flow stream, where each component is at 150 degrees Celsius (°C). This refers to a stream containing one or more impurities with boiling points exceeding a certain value. Stream 313 Each of 314 and 315 is one or more towers, one or more process steps, or one or more for further separating the desired monomer and solvent from the waste stream It can include an operation scheme.

[0023] Referring to Figure 4, residual monomers and solvents are separated and recovered from the waste stream. A schematic representation of one embodiment of the process of the present invention, generally shown in reference number 400, for the purpose of A plot chart is shown. In the embodiment shown in Figure 4, process 400 is a distillation column. Including 410. In process 400, the waste stream 411 is fed to tower 410. The mixture of residual monomers and solvents contained in the waste stream is in the waste stream. Separated from other undesirable waste products, the mixture of monomer and solvent is a mixed monomer. - Exits tower 410 via solvent stream 412. Mixed monomer / solvent stream 41 The mixture of residual monomers and solvent contained in 2 is, for example, styrene monomer, acrylic It may contain nitrile monomers and solvents such as toluene. Then, mixed monomer / solvent. The medium stream 412 is recovered, and the CPP product production process 100 (shown in Figure 2) is performed. It can be recirculated back into the Nomar supply stream 121. Bottom stream from tower 410 Ream 413 can be transferred for further processing, storage, or disposal. Tower 41 The upper overhead stream 414 from 0 is used for further processing, storage, or disposal. It can be forwarded to [location].

[0024] In one embodiment of the process shown in Figure 4, mixing of monomer and solvent stream 412 The mixture of monomer and solvent exiting tower 410 through the combined stream is, for example, 50% by weight. ~65% by weight of solvent, 20%~30% by weight of styrene, 15%~20% by weight of styrene Contains a combination of crironitrile, less than 1% by weight of water, ethylbenzene, and heavy substances. It is possible.

[0025] Referring to Figure 5, for separating and recovering residual monomers from a waste stream , a schematic flowchart of another embodiment of the process of the present invention, generally shown by reference number 500. The diagram is shown. In the embodiment shown in Figure 5, process 500 is performed in the first distillation column 5 The process includes 10 and a second distillation column 520. Process 500 separates styrene monomer and It can be used for recovery, and this is then used in the CPP product production process 10 It can be recycled back into monomer supply stream 121 (shown in Figure 2). In process 500, the waste stream 511 is fed to the first tower 510, and the waste Supply stream 511 consists of three streams: (1) a solvent side stream containing toluene, etc. (2) bottom stream 513 containing styrene, and (3) mostly acrylic It is separated into overhead stream 514 containing an azeotropic mixture of lilonitrile and water. The bottom stream 513 from column 510 is fed into the second distillation column 52 as the supply stream 513. Move to 0, and the bottom supply stream 513 has three other streams: (1) Styrene mono (2) Marside stream 521, (3) Bottom stream 522 which may be a waste stream , and (3) ethyl benz It is separated into the upper overhead stream 523, which includes the stream. Then it exits tower 520. The ethylene monomer stream 521 is recovered and the CPP product production process 100 (shown in Figure 2) is carried out. It can be recycled back to the monomer supply stream 121 (to tower 510). These toluene solvent sidestream 512 can be moved to storage or CPP Pro You can also recirculate it back to Seth.

[0026] Referring to Figure 6, for separating and recovering residual monomers from a waste stream , a schematic flowchart of yet another embodiment of the process of the present invention, generally shown in reference number 600. —A chart is shown. In the embodiment shown in Figure 6, process 600 is first steam The process includes a distillation column 610 and a second conventional distillation column 620. In process 600, waste stri Stream 611 is supplied to the first tower 610, and waste supply stream 611 is supplied to three towers. Ream: (1) Styrene mono that can be recycled back into the CPP production process 100 (2) Marside stream 612, (3) bottom stream 613, and (4) acrylon Separation into an upper overhead stream 614 containing a compound mixture including toryl and water. The overhead stream 614 from tower 610 is used as the supply stream 614. Then it moves to the second distillation column 620, and the upper overhead feed stream 614 is another three The stream: (1) Mostly composed of acrylonitrile and water, and containing toluene. (2) a waste stream 621 which can have (2) mainly composed of ethylbenzene Bottom stream 622, (3) which may be stream and may contain toluene The majority is toluene and can be moved to storage, or used in CPP production processes. It is further separated into sidestream 623, which can be recirculated back to 100.

[0027] Referring to Figure 7, for separating and recovering residual monomers from a waste stream , a schematic flowchart of yet another embodiment of the process of the present invention, generally shown in reference number 700. —A chart is shown. In the embodiment shown in Figure 7, the process system 700 is The process includes an extraction distillation column 710 and a separation distillation column 720. Process 700 is a prior art process. In the past, it has been difficult to produce acrylonitrile from an azeotropic mixture of acrylonitrile and water. It can be used to separate and recover tolyl monomers. Then the recovered Acrylonitrile monomer is used in the CPP product production process 100 (shown in Figure 2). It can be recycled back into the nomer supply stream 121. In process 700, The supply stream 711, containing an azeotropic mixture of crironitrile and water, is an extractive distillation solvent (stream). (as shown by Reem 722) is also supplied to the extraction distillation column 710, and the bottom stream Room 712 exits Tower 710 and enters the upper overhead purification chamber of acrylonitrile 713. The stream exits Tower 710 near the top of the tower. The bottom stream 712 exiting Tower 710 is water and other products such as extraction solvents. In the preferred embodiment shown in Figure 7, the bottom The supply stream 712 can be supplied to the separation tower 720, and in the supply stream 712 The contained water (an undesirable product) can be separated from the desired extraction solvent. Water Stream 721 exits Tower 720 near the top of Tower 720, and exits Tower 720 at the bottom. Stream 722 is to recirculate and return to the extraction distillation column 710 via Stream 722. It is possible.

[0028] In other embodiments, the extraction and distillation scheme 700 shown in Figure 7 is, in one embodiment, shown in Figure 5 In one embodiment, scheme 500 is shown in Figure 500, or in another embodiment, scheme 600 is shown in Figure 6. They can be used in combination. For example, scheme 700 can be combined with scheme 500. When used together, stream 514 is supplied to tower 710 via stream (711). Yes, this is as supply stream 814 in the separation scheme 800 shown in Figure 8. This will also be discussed below. When scheme 700 is used in combination with scheme 600, Reem 621 becomes the supply stream (711) to tower 710.

[0029] Referring to Figure 8, residual monomers and solvents are separated and recovered from the waste stream. A general implementation of the process of the present invention, generally indicated by reference number 800, for the purpose of A schematic flowchart of the configuration is shown. In the embodiment shown in Figure 8, the process system 800 is a machine that performs several operations to separate and recover several monomers and solvents. It is a combination. Process 800 is, for example, a first distillation column 810, a second distillation column 82 Process 800 includes, for example, an extraction distillation column 830 and a separation distillation column 840. ethylene monomer, acrylonitrile monomer from an azeotropic mixture of acrylonitrile and water It can be used to separate and recover solvents such as toluene. (See Figure 8) In the general embodiment shown, towers 810, 820, 830, and 840 are It can have one or more supply streams and one or more discharge streams, respectively. In addition, towers 810, 820, 830, and 840 each have an upper overhang. After the stream, it is incorporated into the process scheme shown in Figure 8 to remove overhead. It may include a condenser (not shown) that forms a force stream, and towers 810, 820, 83 0 and 840 respectively represent the process scheme shown in Figure 8 after the bottom stream. Includes a reboiler (not shown) incorporated into the bottom or heavy material output stream. It is possible.

[0030] Referring again to Figure 8, the waste supply stream 811 is supplied to the first distillation column 810. The waste stream 811 is divided into three streams: (1) Overhead stream 814, (2) side stream of solvent such as toluene 812, and (3) bottom stream It is separated into stream 813. The overhead stream 814 is extracted from the first distillation column 810. The material then proceeds to further processing in the distillation column 830 (described below in this specification). Idstream 812 moves from tower 810 to storage, or returns to process 100. It is circulated and returned. The bottom stream 813 flows from column 810 to the second distillation column 820. The process will then proceed to the next step.

[0031] When the first distillation is carried out in column 810, the reboiler temperature for distillation is, in one embodiment, 5 0°C to 90°C, in another embodiment 60°C to 75°C, and in yet another embodiment 60°C The temperature can be up to 65°C. The reboiler pressure in tower 810 is 0.5 pounds / square in one embodiment. One inch (psi) (3.4 kPa [kilopascals]) to 5 psi (34.4 kPa), In another embodiment, 0.5 psi (3.4 kPa) to 2 psi (13.8 kPa), and In yet another embodiment, 0.7 psi (4.8 kPa) to 1.1 psi (7.6 kPa) It is possible.

[0032] Referring again to Figure 8, the bottom stream 813 from tower 810 is the supply stream 8 As 13, it is supplied to the second distillation column 820 and the bottom stream 813 has three streams. M: (1) Overhead stream 823, (b) Styrene side stream 82 1, and (3) separate into bottom stream 822. Overhead stream 823 , containing unwanted impurities in the CPP process, therefore, overhead Stream 823 can be discarded. Additional processing can be performed on Stream 823. However, such processing would not be practical for recovering relatively small amounts of valuable components. The styrene monomer sidestream 821 is recovered and recycled from column 820. Move to the storage area or container. The bottom stream 822 is also desired in the CPP process. It contains impurities that cannot be removed, and therefore the bottom stream 822 can be discarded.

[0033] When performing the second distillation in column 820, the reboiler temperature for distillation is, in one embodiment, 4 0°C to 85°C, in another embodiment 55°C to 75°C, and in yet another embodiment 65°C It can be up to 70°C. Above 85°C, fouling can become a major issue. When the temperature drops below 40°C, the temperature inside the capacitor can become negative, and the presence of water can cause ice to form. Alternatively, problems such as hydrate formation may occur. Reboiler in Tower 820 The pressure, in one embodiment, is 0.4 psi (2.8 kPa) to 4 psi (27.6 kPa). In another embodiment, 0.4 psi (2.8 kPa) to 2 psi (13.8 kPa), and In yet another embodiment, 0.6 psi (4.1 kPa) to 0.9 psi (6.2 kPa) It is possible.

[0034] Referring again to Figure 8, the overhead stream 814 from the first distillation column 810. This is used as supply stream 814 and is supplied to the extraction distillation column 830, and the supply stream 814 in two streams: (1) Acrylonitrile overhead stream 8 32, and (2) the mixture of the extraction distillation solvent and water is separated into the bottom stream 831.

[0035] The acrylonitrile overhead stream 832 is recovered and recycled from tower 830. It moves to a circulating process or storage. The bottom mixture stream 831 separates from column 830. The process then moves to the dedistillation column 840 for further processing.

[0036] For example, in the extraction distillation operation that occurs in distillation column 830, the extraction distillation scheme is used The extraction solvent used is, for example, tripropylene glycol (TPG), which has a high water-to-water ratio. Polar solvents with affinity; methylpropylene glycol (MPG); dipropylene glycol Dipropylene glycol (DPG), ethylene glycol; dipropylene glycol monomethyl ether, Other products from the glycol ether family, such as propyl glycol methyl ether. This may include substances, and mixtures thereof.

[0037] When performing extractive distillation in column 830, the reboiler temperature for extraction is 45°C in one embodiment. ℃~75℃, in another embodiment 50℃~60℃, and in yet another embodiment 50℃~ The temperature can be 55°C. The pressure in tower 830 is 0.8 psi (5.5 kPa) in one embodiment. ~10 psi (68.9 kPa), in another embodiment 1 psi (6.9 kPa) ~ 5 ps i(34.4kPa), and in yet another embodiment where extraction is the most economical operation, 1 It can range from 0.1 psi (7.6 kPa) to 1.9 psi (13.1 kPa). See 75 above. When temperatures exceed °C and pressures exceeding 68.9 kPa, styrene, acrylonitrile, or Fouling due to the automated polymerization of that combination could be a problem. (As mentioned above, 45°C) If the temperature and pressure fall below 5.5 kPa, additional refrigeration and vacuum costs must be considered. It is necessary.

[0038] Other embodiments as an alternative to and substitute for the operation in the extraction distillation column 830 So, the solvent and monomer are, for example, involved in film composition including vapor permeation and pervaporation. Separation, adsorption to suitable adsorbents such as molecular sieves, and other similar operations or separation The waste can be separated from the waste stream and water using a separation method (not shown).

[0039] Referring again to Figure 8, the bottom mixed stream 831 from column 830 is separated into column 8 Used as supply stream 831 to 40, supply stream 831 to two streams M: (1) Overhead stream of water 842, and (2) Bottom stream of extractive distillation solvent The stream separates into stream 841. The overhead stream 842 of water flows from tower 840 to the wastewater treatment plant. Move to the processing and equipment. The bottom solvent stream 841 is as shown in Figure 8. It can be recovered and recycled back into the extraction distillation column 830, or moved to storage. .

[0040] When performing separation distillation in column 840, the reboiler temperature for distillation is 15 in one embodiment. 0°C to 250°C, in another embodiment 175°C to 235°C, and in yet another embodiment The temperature can be 200°C to 210°C. The reboiler pressure in tower 840 is 5 ps in one embodiment. i (34.5 kPa) to 55 psi (379.2 kPa), in another embodiment 20 psi (137.9kPa) to 50psi (344.7kPa), and in yet another embodiment This can range from 40 psi (275.8 kPa) to 50 psi (344.7 kPa).

[0041] In some embodiments of the process of the present invention, for example, as described above, generally, waste The material stream has an initial solvent content of 20% to 60% by weight, and 10% to 50% by weight. Initial content of styrene monomer, 5% to 35% by weight of acrylonitrile monomer. Initial content: Initial concentration of ethylbenzene at 0% to 5% by weight, and water at 0% to 5% by weight. It can contain an initial content of [substance] and an initial content of heavy substances of 0% to 5% by weight. Next, the solvent, styrene monomer, and acrylonitrile monomer are separated from the waste feed stream. In a preferred embodiment, the waste stream then contains 0% to 30% of the reduced solvent. Contains a large amount, 0% to 85% by weight of reduced styrene monomer content, 0% to 20% by weight A decrease of % in acrylonitrile monomer content, and a decrease of 0% to 5% by weight. The water content and the reduced content of undesirable heavy substances in the range of 0% to 10% by weight. It can contain a certain amount.

[0042] In other embodiments, the process of the present invention is carried out to obtain an optimal amount of useful monomer and solvent. The medium can be advantageously removed. For example, in one embodiment, a small amount of the waste stream At least 30% of the solvent can be removed from the waste stream, At least 10% of styrene monomer can be removed from the waste stream and disposed of. At least 10% of acrylonitrile monomer in the material stream is in the waste stream. It can be removed, and at least 90% of the water in the waste stream can be removed from the waste stream. It can be removed from it.

[0043] The monomers and solvents removed from the resulting waste stream are then removed from the waste stream. Includes a stream that can be substantially purified once recovered. For example, one embodiment So, the solvent stream removed from the waste stream is at least Styrene monomer can have a purity of 90% and can be removed from waste streams. The stream can have a purity of at least 98% and can be removed from the waste stream. The acrylonitrile monomer stream must have a purity of at least 90%. can.

[0044] Referring again to Figure 2, we see monomers and solvents (e.g., acrylonitrile, styrene). (Toluene, ethylbenzene, and water) are recycled from waste stream 142 to the recycle stream. When separated as M211, in a preferred embodiment, the monomer and solvent are CPP-produced To reuse when preparing the product, a single reactor is connected via Stream 211, The waste is then recirculated to a series of two or more reactors, such as reactor columns 120 and 130 shown in Figure 2. It can be returned. In another embodiment, monomer and solvent streams are further processed. For this purpose, they can be moved to other facilities or to storage tanks for storage and later use. can.

[0045] Produced using monomers and solvents recovered from waste streams according to the present invention. Modified copolymer polyols (CPPs) (also known as "modified polyols" or "polymer polyols") A blend of polyol compounds (also called "graft polyol") is a blend of polyol compounds. Or it may be a mixture. Such CPP compounds are fully described in the prior art. For example, an example of a process for producing CPP products is U.S. 4,513,12 No. 4, No. 4,588,830, No. 4,640,935, No. 5,854,386 Nos. 4,745,153, 5,081,180, and 6,613,8 It is described in issue 27 and EP1675885. Generally, it is listed in the above references. The method involves dispersing low molecular weight monomers in droplet form in a polyol in the presence of a stabilizer. This process involves converting monomer droplets into solid polymer particles dispersed in a continuous polyol phase. This includes subjecting dispersed monomer droplets to polymerization conditions until the polymerization is complete.

[0046] For example, the CPP product is in polymer polyols, such as polyether polyols. One or more vinyl monomers in SI, e.g., styrene and acrylonitrile By polymerization, or by the polymerization of polyisocyanates and triethanolamines in polymer polyols. in si between amino-functional compounds such as ruamine or hydroxy-functional compounds It can be obtained by a tu reaction. In one preferred embodiment, the CPP product is po Styrene and / or acrylic in polyoxyethylene polyoxypropylene polyol Products obtained by in situ polymerization of lilonitrile, and / or polyoxy Polyisocyanates and amino-functionalized compounds in ethylene polyoxypropylene polyols in sit between a substance or a hydroxyl-functional compound (such as triethanolamine) It may contain products obtained by u-reactions.

[0047] Stability is an important characteristic of polymer polyols. The dispersed phase is polymer polyol When stored, transported, and used, it must remain distributed within the polyol phase for a long period of time. In addition, polymer polyol products are subject to significant temperature fluctuations during storage and transport. It often fluctuates and must remain stable across the entire temperature range. If unstable, some or all of the dispersed polymer phase may settle. Fouling of transport, storage, and processing facilities, inconsistencies in polymer polyol products, This also leads to mismatches in polyurethanes made from polymer polyols.

[0048] Stability is improved by using stabilizers. Stabilizers include polyol-soluble groups and typical polyols. It contains polyether chains that can have a molecular weight of up to several thousand. The stabilizer is The polyol-soluble groups are present on the surface of the dispersed polymer particles. It is thought that the particles are stabilized through the interaction between the group and the continuous polyol phase. Stabilizer One common type is a "macromer" compound, typically a polyether-polyomer. It is a polymerizable unsaturated group, and one or more of the hydroxyl groups are capped with polymerizable unsaturated groups. This type of stabilizer copolymerizes with styrene and acrylonitrile, and so on. Then, the polyol-soluble portion is introduced into the copolymer particles. In some cases, macromer It is partially homopolymerized or copolymerized with small amounts of one or more other monomers. Form a pre-formed stabilizer. This type of macromer and pre-formed stabilizer Examples include, for instance, U.S. Patent Nos. 4,513,124, 4,588,830, and 4 , No. 640,935, No. 4,745,153, No. 4,997,957, No. 5, No. 081,180, No. 5,196,476, No. 5,854,386, No. 5,9 No. 90,185, No. 6,013,731, No. 6,613,827, No. 7,16 Nos. 0,975, 7,179,882, 7,759,427, and 7, Patent No. 776,969, U.S. Patent Application Publication No. US2004-0266958, and U.S. Patent Application Publication No. US20 Patent Nos. 05-0085613, US2007-0060690, and US200 Numbers 9-0281206, EP0786480, EP1,675,885, and It is described in WO2009 / 155427.

[0049] Polyether polyols include, for example, propylene oxide, ethylene oxide, 1 ,2-butylene oxide, tetramethylene oxide, their blocks and / or It contains polymers such as ion copolymers. Polyether polyols are low-level compounds. May contain end-unsaturated compounds (e.g., less than 0.02 meq / g or less than 0.01 meq / g). Examples of such low-unsaturated polyether polyols include, for example, U.S. No. 3,27 No. 8,457, No. 3,278,458, No. 3,278, 459, No. 3,404 Nos. 109, 3,427,256, 3,327,334, and 3,4 As described in issue 27,335, so-called double metal cyanide (DMC) catalysts This includes items made using [the specified method / technique].

[0050] In addition to polyols, low molecular weight monomers, and stabilizers, the production of polymer polyols. Various other components may be present during the process. A polymerization catalyst is preferably present. Polymerization The catalyst preferably generates free radicals under the conditions of the polymerization process. These are initiators. Examples of suitable free radical initiators include peroxides, persulfates, and perborates. This includes peroxy compounds such as percarbonates and azo compounds. Free radical initiation Specific examples of agents include hydrogen peroxide, di(decanoyl) peroxide, and dilauroyl peroxide. t-butyl perneodecanoate, 1,1-dimethyl-3-hydroxybutyl peroxy do-2-ethylhexanoate, di(t-butyl)peroxide, t-butylperoxide Diethyl acetate, t-butyl peroctoate, t-butyl peroxyisobutyrate t-butylperoxy-3,5,5-trimethylhexanoate, t-butyl peroxy perbenzoate Lu, t-butylperoxypibarate, t-amylperoxypibarate, t-butylperoxypibarate Oxy-2-ethylhexanoate, lauroyl peroxide, cumene hydroperoxide t-butyl hydroperoxide, azobis(isobutyronitrile), 2,2'-A This includes zobis(2-methylbutyronitrile), among others. Two or more catalysts may be used. The amount of catalyst is 0.01 weight percent (weight%) based on the weight of the low molecular weight monomer. The amount may be 5% by weight, preferably in the range of 0.0.1% to 3% by weight.

[0051] Molecular weight modifiers, such as chain transfer agents, are other useful components. Examples of these include: Sopropanol, ethanol, t-butanol, toluene, ethylbenzene, trimethyl Low molecular weight aliphatic alcohols such as amines, dodecyl mercaptans and octadecyl mercaptans Mercaptans such as butan, and salts such as carbon tetrachloride, chloroform, and methylene chloride. These include chloroalkanes and other similar compounds. These chain transfer agents are typically used for low molecular weight monomers. Based on weight, in the range of 0.01% to 3% by weight, preferably 0.25% to 2% by weight. It exists in a limited quantity (if not used at all).

[0052] Polymerization can be carried out continuously or in various batch and semi-batch processes. Yes, it is possible. The continuous process involves the sequential polymerization of polyols, stabilizers, and low molecular weight monomers. Characterized by a gradual introduction and the continuous detachment of products. Semi-batch process So, at least a portion of the low molecular weight monomers are introduced into polymerization, either continuously or intermittently. The product is not continuously recovered and is preferably not removed until polymerization is complete. In this process, some or all of the polyols and / or stabilizers are incorporated into the process. These materials can be added continuously or intermittently, but instead, the entire amount of these materials should be added before polymerization begins. It can be loaded into a polymerization apparatus. In a batch process, all polyols, stabilizers, and low-molecular-weight compounds are used. The molecular monomers are packed in at the start of polymerization, and the product is not removed until polymerization is complete.

[0053] The step includes mixing the above CPP reaction product with the isocyanate reaction product. The CPP reaction product produced as described above is further used to make polyurethane foam A reaction mixture composition can be produced. Next, the reaction mixture is produced using a foam production technology. Used in processes for producing polyurethane foam articles by known reaction schemes. It is used. For example, when preparing a flexible polyurethane foam article or product, first Next, materials A and B are prepared. Then, materials A and B are mixed together. Then, a polyurethane foam forming reaction mixture is formed. Next, the reactive blend is reacted The responsive blend is subjected to conditions sufficient to cure, thereby forming a flexible polyurethane foam. The A-side material is at least one isocyanate-containing material (e.g., 2,4- and / or or 2,6-toluene diisocyanate (TDI), diphenylmethane-diisocyanate It may include (MDI) and various isomers or derivatives of MDI, and B side material The material may contain at least one of the CPP products listed above.

[0054] Generally, CPP reaction products are, for example, polymer polyols, for example, polyethers. One or more vinyl monomers (e.g., styrene and acrylonitrile) in a polyol By in situ polymerization of polyisocyanates in polymer polyols and amino-functional compounds or hydroxy-functional compounds such as triethanolamine It may include products obtained by an in situ reaction between the two. Preferred embodiment So, the CPP reaction product is in polyoxyethylene polyoxypropylene polyol. The raw material obtained by in situ polymerization of styrene and / or acrylonitrile The product and polyisocyanate in polyoxyethylene polyoxypropylene polyol and amino-functional compounds or hydroxy-functional compounds (such as triethanolamine) The product obtained by the in situ reaction between the two can be included.

[0055] Other optional additives or compounds may be added to the A-side material, the B-side material, or the A-side material and It can be added to both of the B-side materials. For example, at least one of the optional compounds A crosslinking agent, at least one reactive catalyst, at least one surfactant, a medium such as water, and mixtures thereof may be included.

[0056] Use any of the known blowing agents conventionally used in the production of polyurethane foam. This can be done. Suitable blowing agents include water, low molecular weight halogenated hydrocarbons, carbon dioxide, and It contains low-boiling hydrocarbons. The foaming agent is used in amounts known to those skilled in the art of foam production. It is used.

[0057] In addition to the above materials, for example, flame retardants, defoamers, antioxidants, mold release agents, dyes, pigments, and any number of various additives conventionally used in the production of polyurethane foam, such as fillers. The agent can also be used in the process of the present invention. The above additives can be used to make foam. It is used in quantities known to those skilled in the art in that field.

[0058] Flexible polyurethane prepared from the above polyurethane foam-forming reaction mixture composition The form is formed using a molding process known to those skilled in the art to form articles or products. Formable. Form-forming compositions and forms produced from such compositions Examples of applications include mattresses, furniture cushions, car seats, bumper pads, and sports shoes. Various packaging and seating for medical devices, helmet liners, pilot seats, earplugs, etc. It can be used for a variety of purposes, including seats and other cushioning applications, as well as for various other applications. Cut. [Examples]

[0059] Inventive examples (Inv.Ex.) or comparative examples (Comp.Ex.) The following embodiments are provided to illustrate the present invention in more detail, but are not subject to the claims. It should not be interpreted as limiting the scope. All parts and proportions are not specifically indicated. Unless otherwise specified, it is the weight.

[0060] Example 1 - Separation of monomers and solvents using extractive distillation In acrylonitrile-styrene CPP plants, typically the CPP is stripped The extracted components are collected in waste tanks and disposed of. Waste tanks throughout the manufacturing plant. Disposal of the trim can be costly in itself. Therefore, for recycling, Recalling Nomar would be advantageous for the industry.

[0061] This Example 1 involves various molecules processed by the separation and recovery system process shown in Figure 8. Simulation of a waste stream containing nomer and solvent components. This is an example. The composition of the waste stream is shown in Table I. The schematic process flow sheet is shown in Figure 8. Using this method, monomers (acrylonitrile, styrene) and solvents are extracted from the waste stream. (Toluene) is separated. The recovered monomer and solvent components are used in the CPP production process. (See Figure 2) The material is recycled back into the reaction system, and any unwanted impurities are separated and discarded. In this simulation example 1, excluding styrene, which has a recovery rate of approximately 86%, The purity of each recovered stream was >98%, and the recovery rate was >95%. . [Table 1]

[0062] To generate the data listed in Table I above, you will need the process modeling tool A Use SPENS to design the separation tower. The thermodynamics that can be used in the above example The scientific model could be NRTL (Non-Random Two-Liquid) theory, with any missing binary. The interaction parameters are regressed by obtaining gas-liquid equilibrium data from measured values ​​or literature. It is possible to estimate using UNIFAC (UNIQUAC functional group activity coefficients). It is possible.

[0063] Other Embodiments As described above, one embodiment of the present invention contains (a) a monomer, a solvent, and an impurity. (b) the waste supply stream of step (a) The stream is subjected to conditions for separating monomers and solvents from impurities in the waste stream. (c) a step of subjecting the monomer and solvent to a separation process in one or more streams (d) the steps of recovering the medium and (c) the monomer and solvent streams from step (c) The steps include moving one or more of them to further processing, and the contents of the waste stream The process includes recovering the monomers and solvent present.

[0064] In one preferred embodiment, the waste supply stream of the above process of the present invention is small At least one solvent, at least one styrene monomer, at least one acrylon It contains tolyl monomer, ethylbenzene, heavy substances, and water.

[0065] In another preferred embodiment, step (b) of the above process is performed in the waste stream At least 30 percent of the solvent is removed from the waste stream. Including styrene monomer, at least 10 percent of the styrene monomer in the waste stream is waste Removed from the material stream, and less acrylonitrile monomer in the waste stream Also, 10 percent is removed from the waste stream, reducing the amount of water in the waste stream. At least 90 percent will be removed from the waste stream.

[0066] In yet another preferred embodiment, step (c) of the above process is to remove waste slush The solvent stream removed from the system has a purity of at least 90 percent, and is recovered. The solvent stream and the styrene monomer stream removed from the waste stream. However, the recovered styrene monomer stream has a purity of at least 98 percent. And the acrylonitrile monomer stream removed from the waste stream is at least It also includes recovered acrylonitrile stream, which has a purity of 90 percent.

[0067] As described herein, another embodiment of the present invention involves (I) mono in the presence of a solvent. (II) The reaction mixture of step (I) and step (II) the reaction mixture of step (I) In this process, residual monomers, solvents, and impurities are combined to produce copolymer polyols. The steps of forming the product and (III) the copolymer polyol product with residual monomers and dissolving Separation from the medium and impurities, at least the first strand of the copolymer polyol product The waste product, including the compost, as well as residual monomers, solvents, and impurities, at least two The steps of forming a stream, (IV) A step of recovering the copolymer polyol product stream, comprising the cop This includes a process for producing merpolyol.

[0068] One preferred embodiment of the above copolymer polyol production process is further ( V) In the presence of the solvent from step (I), waste stool of residual monomers, solvent, and impurities. The process includes the step of recirculating the ream into the monomer reaction mixture.

[0069] Another preferred embodiment of the above copolymer polyol production process is a further (V I) From step (III), the waste supply stream, and from impurities in the waste stream. The steps include subjecting the monomer and solvent to a separation process under conditions for separation, and (VI I) The step of recovering monomers and solvents in one or more streams, and (VIII) One or more streams of monomer and solvent from step (VII) The process includes the step of recycling the monomer reaction mixture in the presence of solvent (I).

[0070] As described herein, the present invention also relates to (A) azeotrope of acrylonitrile and water. (B) The step of supplying the mixture to an extraction distillation column, and (B) extracting in the extraction distillation column using the extraction solvent. The steps include distilling acrylonitrile from water by distillation, and from water to acrylonitrile. This includes a process for separating lonitrile.

[0071] One preferred embodiment of the above extraction distillation process involves using tripylene as the solvent. Including the use of recalls.

[0072] Another preferred embodiment of the above extraction distillation process uses an extraction distillation column, and the column pressure The bar is less than 0.15 bar, and the condenser used in the tower is at a temperature of less than 25°C. This includes carrying out the extraction and distillation process described above.

[0073] Another preferred embodiment of the above-described extractive distillation process involves the use of an extractive distillation column in which 50 to 99 percent of the water is removed from the azeotropic mixture. The invention described in the original claims of this application is listed below. [1] A process for recovering monomers and solvents present in a waste stream, (a) Providing a waste supply stream containing monomers, solvents, and impurities, (b) A step of subjecting the waste supply stream of step (a) to a separation process under conditions for separating the monomer and solvent from the impurities in the waste stream, (c) The step of recovering the monomer and solvent in one or more streams, (d) A process comprising the step of moving one or more of the monomer and solvent streams from step (c) to further processing. [2] The process according to [1], wherein the separation process of step (b) includes a distillation process, wherein a mixed stream of monomer and solvent is separated from the waste supply stream in the distillation process, and the separated mixed stream of monomer and solvent separated in the distillation process is recovered in step (c). [3] The process according to [2], wherein the mixed stream of monomer and solvent comprises 50 to 65 weight percent of solvent, 20 to 30 weight percent of styrene, 15 to 20 weight percent of acrylonitrile, less than 1 weight percent of water, ethylbenzene, and heavy substances in total. [4] The separation process of step (b) comprises a first distillation process and a second distillation process in series with the first distillation process, wherein a solvent sidestream is separated from the waste supply stream in the first distillation process, the separated solvent sidestream separated in the first distillation process is recovered in step (c), a mixed stream of monomers and impurities is separated from the waste supply stream in the first distillation process, the mixed stream of monomers and impurities separated in the first distillation process is recovered in step (c), the recovered mixed stream of monomers and impurities is supplied to the second separation distillation process, a monomer sidestream is separated from the mixed stream supplied to the second separation distillation process, and the separated monomer sidestream separated in the second separation distillation process is recovered in step (c), the process according to [1]. [5] The waste supply stream has an initial solvent content of (ai) 20 to 60 weight percent, (aii) 10 to 50 weight percent of styrene monomer, and (aiii) The process according to [4], comprising: (aiv) an initial content of 5 to 35 weight percent of acrylonitrile monomer; (aiv) an initial content of 0 to 5 weight percent of ethylbenzene; (av) an initial content of 0 to 5 weight percent of water; and (avi) an initial content of 0 to 5 weight percent of undesirable heavy substances, wherein after separating at least a portion of the solvent, styrene monomer, and acrylonitrile monomer from the waste supply stream in step (b), the waste stream separated from step (b) comprises: (bi) a reduced solvent content of 0 to 30 weight percent; (bii) a reduced styrene monomer content of 0 to 25 weight percent; (biii) a reduced acrylonitrile monomer content of 0 to 20 weight percent; (biv) a reduced ethylbenzene content of 0 to 3 weight percent; (bv) a reduced water content of 0 to 3 weight percent; and (bvi) a reduced undesirable heavy substance content ranging from 0 to 3 weight percent. [6] The separation process of step (b) comprises a first distillation process and a second distillation process in series with the first distillation process, wherein a sidestream of a first monomer is separated from the waste supply stream in the first distillation process, the first monomer sidestream separated in the first distillation process is recovered in step (c), a mixed stream of a second monomer, water, and solvent is separated from the waste supply stream in the first distillation process, the mixed stream of the second monomer, water, and solvent separated in the first distillation process is recovered in step (c), the recovered mixed stream of the second monomer, water, and solvent is supplied to the second separation distillation process, a mixed stream of the second monomer and water is separated from the mixed stream supplied to the second separation distillation process, the mixed stream of the second monomer and water is recovered in step (c), a solvent stream is separated from the mixed stream supplied to the second distillation process, and the solvent stream is recovered in step (c), as described in [1]. [7] The separation process of step (b) comprises a first extractive distillation process and a second separation distillation process in series with the first extractive distillation process, wherein a stream of an azeotrope mixture of monomer and water and a stream of extraction solvent are supplied to the first extractive distillation process, a stream of monomer is separated in the first extractive distillation process, the monomer separated in the first extractive distillation is recovered in step (c), a mixed stream of extraction solvent and water is separated in the first extractive distillation process, the mixed stream of extraction solvent and water is recovered in step (c), the recovered mixed stream of extraction solvent and water is supplied to the second separation distillation process, a stream of extraction solvent and a stream of water are separated in the second separation distillation process, and the stream of extraction solvent and the stream of water are recovered in step (c), the process according to [1]. A copolymer polyol prepared from at least a portion of the monomer stream and at least a portion of the solvent stream recovered in step (c) of the process described in [1]. [9] A process for producing copolymer polyols, (I) A step of providing a reaction mixture of monomers in the presence of a solvent, wherein at least a portion of the monomers and at least a portion of the solvent in the reaction mixture are the recovered monomers and recovered solvent recovered by the process described in [1], (II) A process comprising the step of subjecting the reaction mixture from step (I) to reaction conditions to form a copolymer polyol product.

[10] A process for separating acrylonitrile from water, (A) A step of supplying an azeotropic mixture of acrylonitrile and water to an extraction distillation column, (B) A process comprising the step of distilling the acrylonitrile from water by extractive distillation in the extractive distillation column using an extractive solvent.

Claims

1. A process for recovering and reusing monomers and solvents present in a waste supply stream derived from a copolymer polyol manufacturing process, (a) Providing a waste supply stream derived from a copolymer polyol manufacturing process, containing styrene monomer, acrylonitrile monomer, solvent, water and impurities; (b) A step of subjecting the waste supply stream of step (a) to a separation process under conditions for separating the monomer and solvent from the impurities in the waste stream. [Here, the separation process is (i) Separating the waste feed stream in the first distillation column to form a first overhead stream containing acrylonitrile monomer and water, a first side stream containing a solvent, and a first bottom stream containing styrene monomer, (ii) The first bottom stream is supplied to a second distillation column to form a second overhead stream containing impurities, a second side stream containing styrene monomer, and a second bottom stream containing impurities, (iii) The first overhead stream is supplied to an extraction distillation column to form an extraction overhead stream containing acrylonitrile monomer and an extraction bottom stream containing water and an extraction solvent, (iv) The extraction bottom stream is supplied to a third distillation column to form a third overhead stream containing water and a third bottom stream containing the extraction solvent. [including] (c) A step of recovering the monomer and solvent from the first side stream, the second side stream and the extraction overhead stream, (d) A step of moving one or more monomers and solvents from step (c) to a supply stream in the copolymer polyol manufacturing process, A process that includes this.

2. The process according to claim 1, wherein the waste supply stream contains (ai) an initial content of 20 to 60 weight percent of a solvent, (aiii) an initial content of 10 to 50 weight percent of a styrene monomer, and (aiii) an initial content of 5 to 35 weight percent of an acrylonitrile monomer, and after separating at least a portion of the solvent, styrene monomer, and acrylonitrile monomer from the waste supply stream in step (b), the waste stream separated from step (b) contains (bi) a reduced solvent content of 0 to 30 weight percent, (biii) a reduced styrene monomer content of 0 to 25 weight percent, and (biii) a reduced acrylonitrile monomer content of 0 to 20 weight percent.

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